Pectus Meum Est Vitam Mea
by Totally-Out-Of-It
Summary: A Holmes is nearly impossible to kill, unless they give their heart away. Sherlock doesn't mind giving John his heart, because he knows John will take care of it. Mycroft does not quite agree. Johnlock.


**Pectus Meum Est Vitam Mea**

A Holmes is nearly impossible to kill, unless they give their heart away. Sherlock doesn't mind giving John his heart, because he knows John will take care of it. Mycroft does not quite agree.

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 _Pectus Meum Est Vitam Mea = My Heart is My Life_

 _'Cor'_ is another possible translation for 'heart' but my research said ' _pectus_ ' meant 'the seat of emotions' so I thought that fit better than the physical heart. Apologies for any butchering of Latin in that title. I tried.

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Sometimes the biggest secrets are revealed with the smallest mistakes.

Mycroft guarded his heart like a lion with its cubs. His heart was sealed inside a steal vault twenty feet thick buried a hundred feet underground surrounded by booby traps that would make the Hive in Resident Evil cringe in fear. He would not simply give it away to anyone who treated him kindly. His heart was his weakness and he would rather give up queen and country than let anyone have that kind of power over him.

His mother and father were quite the same in their youth. They gave their hearts to each other because they were the same, with their hearts as weaknesses, and knew that they could trust each other to do what was necessary to protect something so precious.

His mother's line went back generations with this same idea, this same weakness, this same method of self preservation. His father's line was more scattered, but Mycroft was certain the same was true for him as well.

He'd thought his brother, Sherlock, who spurned the world almost as much as Mycroft himself, would never falter. Sherlock had used callous truths and caustic wit to drive people away, to stop anyone from wanting his heart even if he were willing to give it. Only three people had ever really gotten through that self defense: the long suffering Lestrade, the unflappable Mrs. Hudson, and the curious Dr. Watson. But Mycroft had allowed Anthea through his first line of defense as well, so the brothers were the same.

There should have been no reason to worry for his little brother's safety, for his brother's heart.

Mycroft learned how wrong he was when he made an unexpected visit to Baker Street. Of course, Sherlock didn't seem surprised to see him, but Mrs. Hudson was obviously thrown and John Watson, though he hid it well, wasn't sure what to make of the visit either.

"Um. Tea, Mycroft?" John offered once the brothers were seated across from one another in the living room.

"That would be lovely, thank you," Mycroft accepted with equanimity. John could make a passable cup, if not something quite up to Mycroft's standards.

Sherlock and he said nothing as John puttered around in the kitchen. Almost every time John opened a cupboard or appliance, he let out a sound of either surprise or annoyance from finding Sherlock's experiments everywhere. He had to clean the kettle of one, and the sink was full of another, the tea was hidden behind a third, and a fourth and fifth were taking up residence in the fridge.

"You could perhaps do more cleaning up around the place, Sherlock," Mycroft noted, casting his eyes around with disinterest.

Sherlock huffed but otherwise ignored him. He was facing the mantle but it was obvious his focus was elsewhere by the almost glazed look in his eyes.

Just as John picked up the tea cups to bring them to the brothers, his phone began to trill loudly in his pocket. John jumped almost imperceptibly in surprise, but the shock was enough to loosen his grip on one of the cups and it shattered on the floor.

"Oh bleeding Christ," John cursed, jumping away from the mess. Tea from the second cup splashed on his right hand and he hissed, hurrying to set it aside and pour cool water on his hand before cleaning it. The phone stopped ringing.

That was the moment Mycroft noticed. That was the moment Mycroft knew he'd been wrong.

Across from him, Sherlock shifted, clasping his hands in a way that had his left hand almost fully covering his right. Still, Mycroft had seen the way the skin of Sherlock's right hand turned lightly red, as if from a mild heat burn.

"Sherlock-" he began sternly.

"You'll get your tea, Mycroft," Sherlock interrupted as if nothing had happened. "And then you can say whatever it was you came to say and get out."

John shook his head at Sherlock from the kitchen, where Sherlock could not see him, but said nothing. It was obvious that he thought the feud between brothers silly and childish, but he wasn't going to step in and try to fix it for them. For that, Mycroft was grateful. He hated people sticking their noses in places they didn't belong. John Watson should not have come between Mycroft and Sherlock Holmes.

Now John was kneeling to clean up his mess, one hand with a towel to soak up the tea and the other picking up the shattered bits of ceramic that had once been a cup.

"You should have told me," Mycroft continued, something like betrayal simmering under his skin. "You know how serious this is."

That burn on Sherlock's hand, the one that had not been there before John Watson spilled hot tea on himself, meant that Sherlock had done the unimaginable. He'd given someone, he'd given a common injured ex-soldier, his heart.

Sherlock heaved a put upon sigh, as if the conversation had already made him weary beyond belief. "I know that it is none of your business."

Mycroft narrowed his eyes at his little brother. "It damn well is my business," he refuted. "You put yourself at risk like this and think to hide it from me." A huff of breath. "I thought you had more sense than this."

"It seems I was doing a bang up job of it until you decided to invade my home, Mycroft," Sherlock shot back. His gaze was as hard as Mycroft's, though defensive where Mycroft was on the attack. "It did not concern you and it never will." He looked back to the mantle as if he had not a care in the world.

Mycroft was shocked. How could Sherlock think this didn't concern him? They were family. They were from the same line of long-lived beings, raised on logic and learning. If Sherlock gave his heart away, everything would change. His entire life would change.

"Listen to me, Sherlock," Mycroft said in a deadly serious, low voice. John was making new tea in the kitchen and Mycroft didn't want to be overheard. "When you decided to try a veritable cocktail of drugs simply for the experience, I did not stop you. When you decided to chase criminals across the underbelly of England, I allowed it. I did this because I knew you couldn't get hurt."

Sherlock gave a derisive snort, as if to say that _Mycroft_ hadn't allowed anything. Mycroft ignored it for the sake of the argument at hand. There was no use getting sidetracked from what was truly important.

"But this I cannot allow," he continued. "You, giving the one thing that could kill you to such a common man-"

"There is nothing common about him," Sherlock interrupted, suddenly locking eyes with his brother again. His eyes were flashing like sharpened flint, so much anger in them that Mycroft, for a moment, could not respond.

"Opinions aside," Mycroft continued, trying to temper that emotion with reason. With logic. "He has nearly died at least three times in his life already. Could you not have chosen someone a bit more suitable?"

Sherlock knew, as all Holmes did, that if they gave their heart away, they could die. If any harm came to this feeble, human male, Sherlock would be harmed as well. So why had his brother not done more to keep his heart in its rightful place, safe and sound in his own chest? Certainly he must have realized that John Watson was getting too close, was overcoming his defenses. So why hadn't he stopped it? Did he want to die?

Sherlock's expression did not waver. "You know as well as I, Mycroft, that no one is more suitable. The entire world is filled with liars, thieves, and beggars. If I chose to rely on one who has _cheated_ death at least three times in his life, then you have no place to demand any more of me."

If only Mycroft could believe that this had been a choice made through reason, that his brother had given his heart to Dr. Watson because he had looked at all the pros and cons and seen that John was good at surviving terrible situations. The truth was that Sherlock had not chosen to give his heart away. No, somehow this average man – average intelligence, average skill, average curiosity, average faults, average expected lifespan – had broken through the countless defenses Mycroft knew Sherlock kept around his heart. Somehow, this man had stolen it. Sherlock probably didn't realize it was given until it was gone. Thieves, indeed.

John came over with the tea just as Mycroft gave a last snip of, "I never considered you a victim of sentimentality, brother."

Sherlock accepted his tea from John and then followed the doctor with his eyes as another cup was presented to Mycroft. John was just returning from the kitchen again with his own cup of tea when Mycroft spoke again.

"Excuse me, John, but could you perhaps excuse us for a few minutes more?" he asked, doing his utmost to appear unperturbed.

While Sherlock narrowed his eyes at his brother, no doubt unhappy that the conversation wasn't over yet, John didn't even bat an eye.

"If you're talking about me, I hardly think I can't be present for it," John defended, sinking down onto the couch with a content sigh.

Mycroft raised an eyebrow while Sherlock looked pleased. He hadn't expected John to hear their conversation, or to understand that he was a large part of it if he did.

Before Mycroft could say anything more, John turned his attention on Sherlock. "How's your hand?"

"It's fine," Sherlock said with a wave of his hand, as if brushing the concern away. There was no hint of red on his pale skin anymore.

Was it possible that John was aware of what Sherlock was? Could John know that his every minute injury also affected Sherlock? Did he know how he burned the youngest Holmes?

"But honestly, Mycroft, if the only reason you're here is to berate me on my choice of protection, then I can assure you I need not hear it, and you may leave with your conscience intact. I will be perfectly alright," Sherlock said dismissively.

Mycroft frowned. "I hardly believe that," he said, taking a sip of his tea. It wasn't quite strong enough for his liking. "You do realize that your life is at risk if you do not take steps to protect yourself?"

"As is any man," Sherlock rebuked. "Do not think me stupid, Mycroft, or I shall never forgive you. We make our own choices in this life. What you chose to do with yours and what I chose to do with mine are separate and unique. I will not change my mind, nor have my heart moved, by your shallow attempt at familial concern."

Mycroft took several moments to simply drink his tea, though he found no enjoyment in it. The others followed his lead and for awhile the flat was a quiet place, with only the ticking of the clock on the mantle to disturb the heavy silence. Sherlock was angry with him. John was quietly following along, attempting, as all men who knew them do, to figure out the puzzle of the Holmes family. Mycroft was unmoved.

"You do me a disservice, brother," he spoke at last. "My concern for you is hardly shallow. We are family, and I worry that you have made a hasty decision. I urge you to rethink your position, and perhaps your living arrangements as well."

If John were merely a doctor, the risk to Sherlock would be minimized, if he refused to take his heart back from the man. If John continued to follow Sherlock around on cases, his chances of being grievously injured or killed rose to a terrifying high. That was a risk that Mycroft was not willing to take.

"I am aware that I put myself at risk by not paying closer attention to where I put my heart, but I do not think I am quite as at risk as you believe." Sherlock nodded toward John. "I have an excellent doctor taking care of it."

John flushed with the praise and Mycroft rather hated him for it. How had someone so normal, so emotional, ensnared a Holmes? How had he gotten possession of Sherlock's heart?

Sherlock's lips lifted just a fraction, but it was enough to give Mycroft pause. "I am perhaps as safe as I could be." Now the brothers met eyes again. "And I promise you that I have never felt more alive in my life."

No doubt the adrenaline rush from knowing he could potentially die made being alive more of an adventure for Sherlock, but that hardly seemed like reason enough to give his heart away so easily.

"I'll protect him," John spoke up, his voice cutting through the maze of Mycroft's mind. The doctor was sitting as straight backed as if he were up for inspection in the corps, but otherwise he seemed as relaxed as his jumper and tea suggested he should be. "I made a promise, to help and protect him, and I'll do that with or without your permission."

His expression was firm and serious, but warmer than any Mycroft had ever seen on a Holmes or on the men and women who worked for him. It was a look that could inspire loyalty, and suddenly Mycroft began to understand.

John Watson was a common man, but he was one of the most loyal humans Mycroft had ever encountered. From his first meeting with Sherlock, John had never wavered, never doubted. He had turned down Mycroft himself, Moriarty, Irene, Lestrade, and countless others, not once betraying Sherlock's tenuous trust. Nothing had frightened him away and no one had lured him either. That kind of unerring loyalty was rare.

But Mrs. Hudson was loyal as well, sometimes to a fault. The difference between Watson and Hudson could be age, or gender, or occupation. Mycroft wasn't certain what the tipping point was, when Sherlock had lost his heart to John, where Mrs. Hudson could never hope to win it.

"I see that my words will have no effect. Therefore, I will not waste my breath or my time," Mycroft allowed at length, setting his empty tea cup down on the table before him. "Know this, though, Sherlock. I do not approve. But this is your mess, dear brother, and so I leave you to soak in it."

He left without goodbye and received none in return. When he was safely in his car and being driven back to his own home, Mycroft made a decision. If his brother could not be trusted to protect himself, then Mycroft would do it for him. If that meant scaring the good doctor away, then so be it.

Suddenly, Mycroft was brought back to his earlier thought – from John's first meeting with Sherlock. John was Sherlock's flatmate. John was Sherlock's blogger. John was Sherlock's partner, in justice or in crime. From the moment they met, John had accepted all that his brother was – genius, skills, and flaws – with aplomb. Accepted it and revered it.

That must've been it, the key to the last door of Sherlock's vaulted heart. And it was why nothing Mycroft could ever do would make the two men separate from each other. The older Holmes knew this with every fiber of his being.

Mycroft could not accept that his brother was no better than a mortal now. He thought he understood how it had happened, but he would not stand idly by and watch his brother throw away his life. They could be nearly immortal if they chose, but Sherlock had tossed that aside. One misstep on a case and it would be all over.

No. Mycroft Holmes would not let his brother die so easily. London had better sleep with one eye open, because if anyone laid a hand on Sherlock, or on Dr. John Hamish Watson - his brother's heart, there would be hell to pay.

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 _fin._


End file.
